Key controlled tumbler lock



March 29, 1955 sso 2,704,934

KEY CONTROLLED TUMBLER LOCK Filed Jan. 22, 1951 5 Shets-Sheet 1 Fig. 1

NVENTOR FABIAN NILSSON Vim gm ATTORNEYS.

March 29, 1955 sso 2,704,934

KEY CONTROLLED TUMBLER LOCK Filed Jan. 22, 1951 5 Sheets-Sheet 2 Fig. 3

l NVENTOR FABIAN NILSSON CMM'M ATTORNEYS.

March 29, 1955 F. NILSSON 2,704,934

KEY CONTROLLED TUMBLER LOCK Filed Jan. 22, 1951 5 Sheets-Sheet 3 Fig. 5

'8 I I 1 13 26 I! I 2 6'3 22 35 27" '22 ss 52 7/ 45 x t '80 lNVENTOR FABMN NILSSON av m aiaw ATTORNEYS.

March 29, 1955 F. NILSSON KEY CONTROLLED TUMBLER LOCK 5 Sheets-Sheet 4 Filed Jan. 22, 1951 Fig.6 32 38 20 INVENTOR B FABIAN NILSSON ATTORNEYS.

March 29, 1955 F. NILSSON 2,704,934

KEY CONTROLLED TUMBLER LOCK Filed Jan. 22, 1951 5 Sheets-Sheet 5 Fig. 5

as 02 v 5544 :NVENTQR' FABIAN NILSSON ATTORNEYS.

United States PatCfifQElCtB 2,704,934 Patented Mar. 29, 1955 KEY CONTROLLED TUMBLER LOCK Fabian Nilsson, Stockholm, Sweden Application January 22, 1951, Serial No. 207,086

18 Claims. (Cl. 70-352) This invention concerns lock, or latch mechanisms, and more particularly lock, or latch mechanisms of the kind comprising one or more axially movable locking pins, or tumblers which are adapted to enter, to a predetermined depth, corresponding perforations in a preferably band-shaped key.

One object of the invention is to provide a lock, or latch mechanism of the kind set forth, in which the key itself, on being inserted into the keyhole, causes the tumbler pins to enter the perforations in the key to release the look.

A further object of the invention is to provide a lock, or latch mechanism in which the key, after the tumbler pins have entered the corresponding perforations to release the lock, is used to effect withdrawal of the lock bolt or latch bolt or similar member by being inserted further into the keyhole so that the key is subjected to bfilckling stresses only and can therefore be made very t in.

Another object of the invention is to design the mechanism in such a manner as to permit the use of a key which is curved in a lateral direction, thus effecting an increased buckling strength of the key so that the thick ness of the key can be decreased still further.

Still another object of the invention is to shape the tumbler pins in such a manner that, on the insertion into the keyhole of a blank key having a coating of wax or the like, misleading impressions of the tumbler pins are obtained in the coating.

Another object of the invention is further to mislead, by the provision of blind tumbler pins, a burglarvwho tries to make a false key.

According to the present invention in a lock, or latch mechanism comprising one 'or more axially movable locking pins or tumblers which are adapted to enter, to a predetermined depth, corresponding perforations in a preferably band-shaped key, the locking pins are so arranged that they are movable into engagement with the perforations in the key by the key proper when it is inserted into the keyhole.

The invention will be hereinafter more fully described with reference to the accompanying drawings showing the invention applied to a latch mechanism for the lock bolt of a door lock provided with a handle for withdrawing the bolt, and in which:

Figure 1 is a vertical axial section through the lock mechanism on the line I-I of Fig. 5.

Fig. 2 is a plan view of the lock mechanism with parts of the cap broken away;

Figure 3 is an end view from the outside of the door;

Figure 4 shows the lock key;

Figure 5 is a cross section on the line VV of Figure 1;

Figure 6 is a cross section on the line VI-VI of Figure 1;

Figures 7 and 8 are axial sections corresponding to Figure 1 but showing the parts in other positions;

Figure 9 is a cross section, on a larger scale, through the slide system in a plane containing a tumbler pin; and,

Figure 10 is a partial view, on the same scale, of the key, illustrating the perforation corresponding to the tumbler pin shown in Figure 9.

As shown in the drawings, the movable parts of the lock mechanism are arranged in an open housing 10, consisting of two substantially rectangular vertically positioned plates 11 which are parallel with each other and are united at their rear ends by a comparatively thick cross wall 12, and at their front ends by two arcuate cross connections 13, which are inserted between upwardly and downwardly projecting rectangular lugs 14 on the plates. The lock housing 10 is supported by a cylindrical steel member 15 which serves as a keyhole escutcheon. For this purpose the steel member 15 is formed on the inside, directly opposite the keyhole 16, with a deep diametrical slot 17 in which the lock housing 10 engages with a sliding fit. For adjustment of the lock housing 10 to correct elevation with respect to the keyhole 16 during assembly of the lock, there are provided two set screws 18 which pass through holes in arcuate yokes 19, which bridge the ends of the slot 17 and enter threaded holes in the cross connections 13 of the lock housing.

Against the bottom of the slot 17 the lock housing 10 is rigidly pressed by means of a cylindrical cap 20, which bears against the lugs 14 and the cross connections 13 through two lugs 21 which project into the slot, the lugs 21 being pressed against the cross connections 13 by means of two screws 22 that pass through holes in the bottom of the cap and enter threaded holes 23 in the steel body 15.

The lock mechanism is assumed to be mounted in an outer door of wood, in the outer panel 24 of which is drilled a circular hole for the cylindrical steel body 15, whereas in the inner panel 25 of the door there is drilled a smaller hole for the cylindrical cap 20 which projects a short distance from the inside of the door. The cylindrical body or keyhole escutcheon 15 is provided at its outer end with a flange in the form of a steel ring 26, which is threaded over the steel body from within and engages a collar on the body. Through the intermediary of said flange, the lock is maintained against the outer side of the door by means of six fastening screws 27 which pass through roomy holes in a ring 28 which is threaded from within over the cylindrical cap 20 and which bears against the inside of the door, and enter threaded holes 29 in the keyhole escutcheon 15.

Also mounted in the door is an ordinary lock which will be described in more detail hereinafter, said lock including a lock bolt 30 which is normally blocked by the latch mechanism within the cap 20 and which in its released position can be pulled back by the aid of ordinary turnable handles provided on the outside and on the inside of the door. In the housing 31 of the ordinary lock a circular opening for the cap 20 and a number of holes which permit passage of the fastening screws 27 referred to above, are also provided.

The mechanism of the lock proper constructed according to the invention will now be described.

Between the two lock housing plates 11 is slidably arranged a main slide 32 provided with two transversely extending guide pins 33 the projecting ends of which enter guide slots 34 provided in the lock housing plates, directly opposite each other, said guide slots 34 being so shaped that the main slide 32 can be displaced in its own plane in the lock housing from its front limit position shown in Figure 1, firstly in a slanting direction inwardly and downwardly to the position shown in Figure 7 and thereafter in the same plane to its inner limit position shown in Figure 8. To keep the main slide 32 in its front limit position and in its rear limit position respectively, there are provided two snap springs 35 each of which at one end engage around a pin 36 secured in the lock housing and at the other end engage around the appropriate projecting end of the rear guide pin 33.

On its under side, the main slide 32 is formed with a straight slot 37 of rectangular cross section, said straight slot being adapted to receive a correspondingly shaped upper flange on the back of an auxiliary slide 38. The auxiliary slide is maintained in the guide slot of the main slide by two pins 39 which pass through the upper flange on the auxiliary slide and enter with their projecting ends two straight guide slots 40 in the adjacent flanges on the main slide, so that the auxiliary slide 38 becomes displaccable with respect to the main slide 32 between a front and a rear limit position. The auxiliary slide is normally locked in the former position, which is shown in Figures 1 and 7, by means of a locking pin 42 which is guided in a bore in the main slide and enters a lock hole 43 in the auxiliary slide under the action of a spring 41.

The underside of the auxiliary slide 38 is part-cylindrical in shape to correspond with the shape of a transversely curved band-shaped key 44 which, at its edges, is guided along two straight guide flanges 45 provided on the inside of the lock housing plates 11 directly opposite the keyhole 16. Below the guide flanges 45, a bottom plate 46 is secured to the lock housing. Underneath said bottom plate, three slides 47, 48 and 49 are axially guided between the lock housing plates 11. The intermediate slide 47 serves as a latch bolt for the lock bolt 30. Normally engaging said latch bolt is a pawl 52 which is pivotable, relative to the lock bolt 30, on a pin 50, and is actuated by a flat spring 51, the lock bolt 30 being normally held by the pawl 52 in its locking position shown in Figure 6 against the action of a spring 53 which strives to pull back the lock bolt to its opening position. The outer slides 48 and 49 form parts of a mechanism for opening the lock from the inside of the door by means of a latch handle and the inner door handle, without the use of a key. Fixed on the latch bolt 47 is a driving pin 54 which passes up through a longitudinal slot 55 in the bottom plate 46 and into a corresponding hole 56 in the auxiliary slide 38. The front side of the driving pin 54 is provided with a notch 57 against the bottom of which the key 44 is adapted to press with its inner end when the key is inserted into the key hole.

Except by means of the locking pin 42, the auxiliary slide 38 is normally coupled with the main slide 32, through two two-part tumbler pins 58, 59 and 60, 61, which are normally maintained each by a corresponding spring 62 or 63 respectively in their lower limit positions shown in Figure 1, in which positions the upper pin pieces 58 and 60 enter both the main slide 32 and the auxiliary slide 38. The movability of the lower pin pieces 59 and 61 in an axial direction is limited by a plate 64 which is secured in a slot in the auxiliary slide 38 and which, with straight edges of large holes provided therein, enters recesses 65 in the pin pieces having plane bottoms, whereby the pins are prevented from turning about their axes. The lower pin pieces 59 and 61 are shaped at their lower ends in a particular manner and are arranged, on the lowering of the slide system 32, 38 to its lower limit position, to enter perforations 66 and 67 in the key, such perforations being so shaped that the pins are lifted to a position in which the joint between the pin pieces coincides with the sliding surface between the main and the auxiliary slides 32 and 38, as will be hereinafter more fully described.

The auxiliary slide 38 also supports a fixed driving pin 68 which projects from the underside of the slide and which on lowering of the slide system 32, 38 enters a circular hole 69 in the key 44 before any one of the tumbler pins 59 and 61 has contacted the key.

On a level with the key 44 in its inserted position, there is provided in one of the lock housing plates 11, a hole through which projects a pin 71, actuated by a spring 70. The pin 71 which is pushed away by the key when it enters the lock, prevents in its normal projecting position, the slide system 32, 38 from being lowered to its lower position under the action of vibration or blows against the lock, it being possible to lift the slide system from its lower position only by means of the key when the latter is pulled out of the lock.

When the door is to be opened from without, the key 44 is inserted through the keyhole 16, the key then sliding along the key guides 45 and against the lock housing walls 11, and entering with its front end, the notch 57 in the driving pin 54. This position of the key is shown in Figure 1. On further insertion of the key, both the latch bolt 47 and the slide system 32, 38 are carried along by the key, the slide system then descending along the guide slots 34 to its lowermost level as shown in Figure 7. During this descent, the driving pin 68 first enters the hole 69 in the key, so that the key is coupled with the slide system, whereafter the tumbler pins 59 and 61 enter the perforations 66 and 67 in the key. Said perforations are so shaped that movement of the tumbler pins with respect to the key is arrested in a definite relative position before the slide has reached its lowermost level, so that during the last part of the descent 9f he slide, the

tumbler pins are raised in the slide system to an extent such that the joints between the respective tumbler pin pieces coincides with the sliding surface between the auxiliary slide 38 and the main slide 32. In said position which is shown in Figure 7, the tumbler pins 58 and 60 no longer prevent relative displacement between the auxiliary slide 38 and the main slide 32, but the auxiliary slide and the main slide are still coupled together by means of the locking pin 42. If now the key is inserted a further distance, still taking with it the slide system in its entirety, the locking pin spring 41 will ride up an oblique cam surface 72 in the lock housing wall 12, the locking pin 42 being then lifted out of engagement with the auxiliary slide 38, so that thereafter the latter is entirely released from the main slide 32. In the fully inserted position of the main slide shown in Figure 8, a wart-shaped bulge provided on the underside of the free end of the locking pin spring 41 enters a depression in the horizontal part of the cam surface 72, causing the main slide to be held with a certain force in its inner limit position. However, the latch bolt 47 still co-operates with the pawl 52, so that the lock bolt 30 is still locked in its projecting position. Movement of the latch bolt from its locking position is effected during the last part of the inserting movement of the key, the auxiliary slide 38 being then displaced with respect to the main slide 32 which is now held stationary by engagement with the transverse cross wall 12, into the limit position shown in Figure 8.

It should be noted that displacement of the slide system 32, 38 from the starting position shown in Figure l to the intermediate position shown in Figure 7, during the first part of the movement, is effected against the action of the snap springs 35. Just before the slide system has reached the intermediate position shown in Figure 7, the snap springs 35 are taken past their dead-centre positions, so that thereafter instead of counteracting the movement, they aid said movement and finally hold the main slide 32 in its inner limit position.

When the key is again pulled out of the lock, the latch bolt 47 is moved back to its locking position. When said position has been reached and the auxiliary slide 38 has thus been pulled back to its original position with respect to the main slide 32, which latter slide is yieldingly held in position by the locking pin spring 41, the main slide is caused to follow because the guide pins 39 secured to the auxiliary slide now bear on the rear ends of the guide slots 40, and the snap springs 35 are now forced back over their dead centre positions. Before said positions have been passed, the lifting spring 41 has slid off the cam surface 72, and the locking pin 42 has returned to its locking position, so that once again the auxiliary slide and the main slide are positively coupled together. When the key is pulled out a further distance, the slide system is lifted back to its upper and front limit position due to the action of the slanting guide slots 34, the tumbler pins 58, 59 and 60, 61 being then first moved to their lower limit positions by their corresponding springs 62 and 63 and thereafter being lifted free from the key. Finally, the driving pin 68 becomes disengaged from the key which can then be freely pulled out of the keyhole, whereas the slide system is forced back by the snap springs 35 to its starting position shown in Figure 1.

To render possible opening of the lock from the inside of the door, a latch handle 73 is centrally journalled in the end of the cap 20, the latch handle having a pinshaped extension 74 which supportingly enters a bearing hole in the rear cross wall 12 of the lock housing. On that portion of the turnable handle, which enters the cap 20, is keyed a hub 75, in the circumference of which is provided a helically shaped slot 76. Entering said slot is a driving pin 77 provided on a cross piece 78 which rigidly interconnects the two slides 48 and 49. Said slides are formed with a notch which, in the normal position shown in Figure 1, leaves a free space for the pawl 52 on the lock bolt 30, the inner limiting wall of the notch being shaped to form a cam surface 79 which, on pulling out of the slides by means of the latch handle 73, engages the pawl 52 and moves the latter out of its locking position, the lock bolt 30 being then automatically pulled back by the spring 53 so that the door can be opened.

To limit the movement of the outer slides 48, 49 there 18 provided in one of the lock housing plates 11, a screw 80 which enters an elongated slot 81 in one of the slides.

The perforations in the band-shaped key, which are adapted to co-operate with the tumbler pins, may be given any desired shape and size. The simplest arrangement is to make the perforations in the form of circular holes and to provide the tumbler pins with tapering ends of circular cross section, the size of the hole then determining the depth to which the pin enters the hole before it is arrested by the key. Alternatively, the perforations in the key may be given a triangular, rectangular or other non-circular form, and the tapering ends of the tumbler pins a corresponding cross-sectional form. It is also possible to provide the respective tumbler pins with ends of uniform thickness, and provide said ends with a projecting shoulder which engages the key adjacent the edge of the hole, thereby arresting the tumbler pin against the key. Other modifications also are conceivable. Irrespective of the form of the perforations in the key, into which the tumbler pins are intended to enter, and the shape of the pins, it is advantageous to give the end proper of the pin an area which is smaller than the area of the perforation into which the pin is intended to enter, in order that no useful impressions shall be obtainable in a blank key which is covered by a layer of wax or the like. The end area is then preferably eccentrically positioned with respect to the perforation in the key.

An example of a suitable shaping of the end of a tumbler pin which is intended to enter a triangular perforation, is shown in Figure 9. The point of the pin has the form of an extension 82 of smaller diameter, the pin tapering towards said extension from a triangular portion 83 which is of uniform thickness and of a crosssectional shape corresponding to the perforation 84 shown in Figure 10, a projecting stop shoulder 85 being provided on said pin portion of uniform thickness. On a blank key provided with a coating of wax, an impression of the narrow pin extension 82 only would be obtained. If a hole 86 is drilled in a key blank with said impression as centre and of a size just sufiicient to permit the triangular portion 83 of the tumbler pin to pass freely. through the hole, that portion 87 of the key against which the shoulder 35 is intended to bear, would at the same time be drilled away, so that the tumbler pin would enter too far into the hole with the result that the surface of separation between the tumbler pin pieces would lie within the auxiliary slide, so that the auxiliary slide and the main slide would remain coupled together.

Since the tumbler pins must be lifted neither too little nor too much, it will be quite impossible for a burglar to find out both the correct size and the correct shape of one or more perforations. If it is desired to mislead a burglar still further, it is possible to provide in the auxiliary slide 38, a number of blind pins 88 and 89 which leave misleading impressions in a blank key having a coating of Wax. The blind pin 88, the guide portion of which has the same diameter as the tumbler pins, and the narrower end portion of which is coaxial with the guide portion, is arranged in line with and behind the tumbler pin 58, 59. Thus, if a hole is drilled in the key, so that on the descent of the slide system, the pin is not lifted to the position shown in Figures 7 and 8, in which position the pin completely fills the bore in the auxlliary slide, the spring actuated tumbler pin part 58 will, on movement of the auxiliary slide with respect to the main slide, be pressed down into the bore, thereby preventing continued displacement of the auxiliary slide with respect to the main slide. In case the guide portion of the blind pin 88 is not positioned in line with the tumbler pin 58, 59, the blind pin should be given a spring actuated upper pin piece of its own similar to that of the tumbler pins. Furthermore, the bottom plate 46 may be provided with holes or with a raised portion 90 with which the blind pin, if it passes through the key, makes engagement, thereby arresting the auxiliary slide. If a hole is drilled for the blind pin 89 which is spring actuated in order to leave impressions which closely resemble the impressions made by the spring actuated-tumbler pins, said blind pin will engage the raised portion 90 or a hole in the bottom plate, so that continued displacement of the auxiliary slide is prevented in this case also.

The invention is not limited to the embodiment illustrated in the drawings, but modifications of various kinds are conceivable without departing from the invention.

What I claim is:

1. In a lock; a casing, a first member slidable in the casing, a second member slidable on the first member, locking pin means normally locking said-members together, an abutment on said second member engageable by a band-shaped key for initial movement of the members in unison by the key when the key is inserted in the lock, said members being guided in the casing so the said initial movement thereof is in a diagonal direction in the casing toward the key, and means comprising end portion means on the locking pin means engageable with the key responsive to the said initial movement of the members toward the key for axially displacing said locking pin means to unlocking position in said members.

2. In a lock; a casing, a first member slidable in the casing, a second member slidable on the first member, locking pin means normally locking said members together, and including shouldered end portion means projecting from one side of the members, a key guide in the casing spaced from the members on the said one side thereof for receiving a band-shaped key, an abutment on said second member in the path of the key so insertion of a key in the guide will engage said abutment and whereby further movement of said key will cause initial movement of said members in unison with each other and with the key, said members being guided in the easing so said initial movement thereof takes place diagonally in the casing toward said key guide, the proper key for operating the lock being provided with perforations to receive and engage said shouldered end portion means for displacing said locking pin means axially in said members into unlocking position.

3. In a lock; a casing, a first member slidably guided in said casing for initial movement bodily diagonally of the casing toward one side of the casing and then movement in the same general direction lengthwise of the casing, a second member on the first member on the side thereof toward the said one side of the casing slidable thereon in the direction of the length of the casing, locking pin means extending through said members transversely of the length of the casing and having shouldered end portion means projecting from said second member on the side opposite said first member, a key guide in the casing extending in the direction of the length thereof spaced from the said end portion means, an abutment on said second member extending across said key guide 5 for engagement by a key inserted therein so pushing the key will cause said initial movement of said first member because of its locked relation to said second member, said key being provided with perforations to receive the ends of said end portion means of said locking pin means while engaging the shoulder means thereof, so that during the said initial movement of said members, the key will an est the locking pin means causing relative movement between the same and said members to move the locking pin means into unlocking position in said members, said second member thereafter being movable by the key independently of the said first member.

4. In a lock; a casing, a first member slidable in the casing, a second member slidable on the first member, locking pin means normally locking said members together, an abutment on said second member engageable by a band-shaped key for initial movement of the members in unison by the key when the key is inserted in the lock, said members being guided in the casing so the said initial movement thereof is in a diagonal direction in the casing toward the key and and further movement of the members is lengthwise of the casing, means comprising end portion means on the locking pin means engageable with the key responsive to the said initial movement of the members toward the key for axially displacing said locking pin means to unlocking position in said members, other locking means connecting said members, and means responsive to a predetermined further movement of said members after the said initial movement for unlocking said other locking means, thereby releasing said members from each other, a lock bolt, means for retaining said lock bolt, said lock bolt retaining means interconnected with said second member so that still further movement of said second member after its release from said first member will release said lock bolt.

5. In a lock; a casing, a first member slidable in the casing, a second member slidable on the first member, locking pin means normally locking said members together, and including shouldered end portion means projecting from one side of the members, a key guide in the 86 casing spaced from the members on the said one side thereof for receiving a band-shaped key, an abutment on said second member in the path of the key so insertion of a key in the guide will engage said abutment and whereby further movement of said key will cause initial movement of said members in unison with each other and with the key, said members being guided in the casing so said initial movement thereof takes place diagonally in the casing toward said key guide, while further movement of said members after said initial movement thereof takes place parallel to said key guide, the proper key for operating the lock being provided with perforations to receive and engage said shouldered end portion means for displacing said locking pin means axially in said member into unlocking position during the said initial movement of said members, other locking means connecting said members, means responsive to a predetermined amount of said further movement of the members for unlocking said other locking means to release said members from each other, a spring actuated lock bolt, a detent on said lock bolt, a slide engaging said detent, said slide operated by continued sliding movement of said second member by the key after its release from the first member to release said lock bolt.

6. In a lock; a casing, a key guide lengthwise of the easing to receive a band-shaped key, a first member slidably guided in the casing for initial movement diagonally toward the key guide and then further movement parallel to the key guide, a second member slidably guided on the key guide side of the first member for movement thereon parallel to the key guide, locking pin means in the members normally locking the members together movable therein at right angles to the key guide into unlocking position, an abutment on the second member engageable by a key pushed into the guide for bringing about movement of said members in unison during the said initial movement of the first member, said locking pin means comprising shouldered end portion means extending from the key guide side of said second member for engagement with a key so a properly perforated key will move the locking pin means to unlocking position during said initial movement, other means locking the members together, means responsive to a predetermined amount of the said further movement of said first member parallel to said key guide after the said diagonal movement thereof for releasing said other locking means and for halting said first member, and said second member being movable independently of said first member upon further movement by the key following the said halting of said first member.

7. An arrangement as set forth in claim 6 which includes a driving pin projecting from the second member adapted for entering a perforation in the key during the initial movement of the members to connect the key positively with the second member.

8. An arrangement as set forth in claim 6 including resilient means urging said first member in a direction opposite to the movement of the key during insertion thereof, and means for retaining the first member in its said halted position until the second member returns to its initial position thereon.

9. An arrangement as set forth in claim 6 in which the key guide is arcuate for receiving a key curved transversely.

10. An arrangement as set forth in claim 6 having a slide movable parallel to the key guide and connected to said second member by the said abutment which is fixed in the slide and is received in a bore in the second member to initiate movement of a lock bolt.

11. An arrangement as set forth in claim 8 in which the said resilient means is an overcenter spring adapted for snapping over center between the position of the first member at the end of the initial diagonal movement thereof and the end of the said further movement thereof parallel to said key guide.

12. An arrangement as set forth in claim 6 in which means are provided for resiliently resisting movement of the first member by the key during the said initial diagonal movement thereof and for assisting movement of the said first member by the key during the said further movement thereof.

13. An arrangement as set forth in claim 6 in which the locking pin means comprises two pins in end-to-end engagement with the plane of abutment normally dis placed from the plane of engagement of the said members.

14. An arrangement as set forth in claim 6 in which a locking member on the casing engages the said first member to lock it in place, the said locking member being displaced from locking position by the insertion of a key in the key guide.

15. In a lock; a casing, a first member in the casing guided therein for sliding movement first in a diagonal direction toward one side, and then lengthwise, a key guide lengthwise of the casing spaced from said one side of the member to receive a band-shaped key, a second member in face-to-face sliding engagement with the said one side of the first member, said members having registering bores extending transversely of the casing, locking pin means in the bores comprising two pins in end-toend engagement, a spring on the first member urging said pins in a direction to locate their plane of abutment within said second member to interlock the members, the one pin having a shouldered end projecting from the second member toward the key guide, an abutment connected with the second member extending across the key guide so a key inserted in the guide will engage the abutment and move the members in unison diagonally of the casing toward the key guide, the proper key for operating the lock having a perforation to receive the end portion of said one pin for shifting the pins in the members during the diagonal movement of the members into position where the plane of abutment of the pins coincides with the plane of engagement of the members, so the second member can be shifted relative to the first member, a second bore in the second member adapted to register with the said bore in the first member during the said shifting movement of the second member, and a pin in said second bore having an end portion engageable with the key whereby the proper key will support said pin in a position with the end thereof in the plane of engagement of said members.

16. An arrangement according to claim 15 in which a stationary abutment in the casing on the opposite side of the key guide from said members is engageable with the end portion of the last-mentioned pin when a key having a perforation to receive the said pin is placed in the lock whereby movement of said members beyond a predetermined limited amount by such an improperly perforated key is prevented.

17. An arrangement according to claim 6 in which the second member includes a blind pin spring urged toward the key guide and engageable with a. fixed abutment in the casing when a key having a perforation that registers therewith is inserted in the key guide whereby such a perforated key will not be operable to move the said members beyond a predetermined limited amount.

18. An arrangement according to claim 6 in which the shouldered end portion means of the locking pin means comprises a small section at the extreme end and a portion tapering outwardly toward the shoulder whereby a misleading wax impression of the perforations required in a key that will operate the lock will be made when a blantll SiiaPCd element having a wax coating is inserted in t e 0e.

References Cited in the file of this patent UNITED STATES PATENTS 271,962 White Feb. 6, 1883 823,221 Jorgenson June 12, 1906 1,163,470 Schoell Dec. 7, 1915 2,379,040 Schori June 26, 1945 2,388,227 Heyer Oct. 30, 1945 

